The broadband white sky surface albedo (BiHemispherical Reflectance) products available from the
MODerate resolution Imaging Spectroradiometer (MODIS) are compared, in joint papers, at regional
and continental scales with similar products generated from the Multiangle Imaging
SpectroRadiometer (MISR) land surface Bidirectional Reflectance Factor (BRF) parameters. This
first paper describes the methodology applied to derive MISR white sky albedos over four spectral
broadbands of interest namely, 0.3--0.7 $\mu$m, 0.4--1.1 $\mu$m, 0.7--3.0 $\mu$m and 0.3--3.0
$\mu$m as well as an evaluation of the strategy adopted to compare the MODIS and MISR products.
The results are very encouraging since the two datasets are showing very good statistical
agreement over large areas and over a full year of measurements, despite the many differences
that exist in the suite of algorithms applied to retrieve these surface quantities from each of
these instruments separately. Large scale analyses of the two MODIS and MISR-derived products have
been conducted and results are shown and discussed in a companion paper (Part II).